Charging Batteries While Trolling

[anothertoy]

Hello there:

I have a 2002 Sailfish with twin Yamaha F225's. I fish for salmon and troll at about 700-900 rpm on one of the motors. The whole area of batteries and charging systems is a bit of a mystery to me. While fishing I'm running fish finder, GPS, vhf radio, stereo and downriggers. I would also like to use the fridge to keep my bait frozen (and beer cold) but have held back because of concerns of draining the batteries. Can anybody give me any advice on how much charge my motor is giving the batteries vs the drain of what I am using?

Thanks for any help.

 

[gerrys]

Likely the total current draw of all the electronics/appliances you are using will exceed the alternator output at that rpm; however, remember the fridge only works intermittently. I would think the motor output would very much slow the drawdown of the batteris sufficiently to allow many, many hours of operation that way. It's very dependent on the size, type and condition of your batteries. I know on my Marlin with GP 27"s, 2 in a bank - we could seemingly go forever in that configuration.

 

[Hookup1]

Yamaha charging

Only one of your engines is wired to the house battery the electronics are on. With both engines off and a load you should see 12.8 volts with a voltmeter at the battery. Start the engines one at a time. The engine wired for auxuliary charging will bring the voltage up to about 13.5.

If not then you need someone to verify the aux charging wire, etc.

I checked the Yamaha altenator output before. I think the spec is 45 amps WOT and 12 amps at idle.

I run the fridge, 2 chart plotters, sounder, radar, XM weather and two bait tank pumps while trolling. Single 27 series deep cycle battery. Not a problem. If you can, setup a voltage data box on you chartplotter so you can keep track of your battery voltage while fishing.

Many of the new electronic devices have 10 to 36 volt input power ranges. This reduces sensitivity to low battery voltages.

 

[Grog]

Check your voltage at trolling speed with all your loads on and see what you have. The GPS doesn't use much, VHF doesn't use much (more when you talk), stereo's varry (stock radio or 500W amps), and downriggers don't always use power. The fridge is a decent draw but depends on how often it's opened (I'd just use ice because the fridge will end up smelling fishy).

 

[CJBROWN]

We have these great debates on here about batteries. I like deep-cycles because they will withstand drawing them down, whereas the combo's or marine-starter or cranking batteries not as much. Deep cycles will start the motors just fine as long as they have sufficient charge. Some don't like the drop in volts while cranking the motors. To fix that requires a couple of different battery banks and switches - gets a lot more complicated. I have never worried about it, sometimes the stereo restarts, or the electronics will reset. They are protected from damage from voltage drops so it's really not an issue.

Check for your auxilliary charging from the outboards, it's an option on the yamahas. This will let you charge two banks. My recommendation is to connect two deep-cycles parallel, and one cranking battery for each motor. Run everythng on the two deep-cycles, keep the crankers for just that purpose if you get drawn down. Use the aux charging circuits to keep your crankers topped up.

When you get back to the dock be able to put a smart electronic charger on your deep cycles to get them topped up and kept that way. Your outboards may not be able to get them all the way recharged on your return run.

I have used this setup in all of my boats with good success. If you really need a lot of reserve power, get a pair of 6v golf cart batteries for your 'house' and wire them in series. They offer about 200 amp hours of reserve. 'Course your outboards won't be able to recharge them if they get discharged, unless you're running for many hours. You definately need an auxilliary charger that runs on shore power.

I doubt you would ever run out of power with a pair of group 27 deep cycles with at least some trolling. Sitting for days on the hook would be a different story.

 

[BobP]

Consider Group 29s or ene 31s, they fit in same box as 27s. They have a bit more juice.